A home base station (Home NodeB, referred to as HNB for short in the following) is a femtocell, oriented to a residence environment or an enterprise environment. In the scenario of an enterprise network or a hot spot, an HNB group may be used to provide continuous coverage for the enterprise network or the hot spot. The HNB is connected to a core network (referred to as CN for short in the following) through a home base station gateway (Home NodeB Gateway, referred to as HNB-GW for short in the following). One HNB-GW is connected to a plurality of HNBs, and coverage of the HNBs may be geographically continuous.
On an HNB network, a coverage range of each HNB is less than that of a macro network cell. One HNB covers a range of about ten meters. When a UE moves on the HNB network, the UE has to handover itself to or reselect another HNB cell frequently, where the handover or reselection is more frequent than that on a macro network.
A status of a cell forward access channel (Cell Fach forward access channel, referred to as CELL_FACH for short in the following) is taken as an example. When a user equipment (referred to as UE for short in the following) moves to a new radio network controller (referred to as RNC for short in the following), the UE starts a cell reselection process. The UE sends a cell update (CELL UPDATE) message to a target cell to trigger a cell update process. The target cell determines a source cell where the UE is located by identifying a U-RNTI in the CELL UPDATE message. Therefore, it must be ensured that the U-RNTI of the UE uniquely identifies a UE on the whole UTRAN. The U-RNTI is comprised of an RNC identity (referred to as RNC-ID for short in the following) and a serving RNC radio network controller radio network temporary identifier.
However, on a home base station network, a U-RNTI management mechanism of the macro network cannot ensure that the U-RNTI is unique. According to the structure of the HNB network, an HNB-GW and all HNBs connected to the HNB-GW are one RNC as a whole from the perspective of the core network CN, and the HNBs under the same HNB-GW share the same RNC-ID. When the registration of an HNB, the HNB-GW sends an RNC-ID to the HNB. When the HNB allocates a U-RNTI to the UE, it can only be ensured that an S-RNTI is unique in the range of the current HNB, but it cannot be ensured whether another HNB under the same HNB-GW uses the S-RNTI. Therefore, it cannot be ensured that the U-RNTI is unique in the HNB-GW; that is, the HNB cannot ensure that the U-RNTI is not used by another HNB under the same HNB-GW.
On the HNB network, when a source HNB allocates a U-RNTI, it can only be ensured that the U-RNTI is unique in the HNB and it cannot be ensured that the U-RNTI is unique in the whole RNC and UTRAN. Furthermore, a target HNB cannot know a U-RNTI allocation situation of other HNBs under the same HNB-GW. Therefore, the target HNB cannot identify the source HNB according to the U-RNTI so that it cannot accurately transfer a cell update message to the source HNB.
If the cell update message is incorrectly transferred to an HNB cell, the cell update process is disordered. For example, a user equipment A moves from a home base station A to a home base station B and resides in home base station B through cell reselection. The user equipment sends a cell update message including a current U-RNTI (allocated by HNB A) of user equipment A to home base station B. If the U-RNTI currently used by user equipment A is allocated by another home base station C to user equipment B, home base station B analyzes the U-RNTI to decide that a source HNB that user equipment A moves from is home base station C, and home base station B forwards the cell update message to home base station C. Home base station C receiving the cell update message, as a source cell, initiates a reposition process for user equipment B. As a result, user equipment B is released by HNB C and is in a state that the network cannot page user equipment B, and use equipment A cannot reside in a cell of the home base station B.
In the prior art, the HNB-GW allocates non-overlapping U-RNTI prefix segment/index or identifier segment to each HNB. When an HNB is connected to the HNB-GW, the HNB-GW designates U-RNTI prefix segment/index or identifier segment that can be allocated to the HNB.
The HNB may report its capability information (the information indicates the number of required U-RNTIs) to the HNB-GW during registration, and the HNB-GW allocates U-RNTI resources according to the capability of the HNB so as to avoid improper use of U-RNTIs among cells resulted from that the same number of U-RNTIs are allocated for HNBs different in load. If an HNB supports at most 16 users, an index value allocated to the HNB is 16 bits (HNB-GW RNC-ID is 12 bits, and the index value of the HNB is 16 bits, and therefore 4 bits can be used to flexibly allocate U-RNTIs).
However, in the prior at, the U-RNTI prefix segments, indexes, or identifier segments allocated by the HNB-GW to the HNB are fixed. This may cause a waste of U-RNTIs and reduce the number of UEs that can be supported on an HNB system.